In particular, in the medical field or the biotechnology field, an automatic analysis device is used which detects a specific biological component, chemical substance or the like contained in a sample such as blood, serum, and urine by causing the sample to react with a reagent. This automatic analysis device needs further improved analysis accuracy in order to achieve a very reliable inspection. For example, when a dispensing nozzle is insufficiently cleaned during a series of analysis-related process, there is a possibility that an adsorbed material remaining in the dispensing nozzle without being completely cleaned may mix with the subsequent sample by being separated from the dispensing nozzle when the subsequent sample is dispensed. This phenomenon is generally called carryover. The carryover affects measurement results.
If a child or an aged person is a patient, only a small amount of the sample can be collected. In addition, in order to ease the burden of the patient or to reduce reagent usage, a trace element of the sample and the reagent may be further progressively used in the future. Therefore, more than ever before, it becomes important to prevent the carryover or contamination in the dispensing process of the sample and the reagent. With regard to a cleaning method for the dispensing nozzle, various methods of using a cleaning solution have been proposed (refer to PTL 1).